The mesa demos package contains es1_info and es2_info, which list the extensions and capabilities of the es1 and es2 implementations on the system, similar to glxinfo except using egl. Attached should be a modified mesa-8.0.1 ebuild that builds and installs them, protected by the 'gles1' and 'gles2' USE flags Reproducible: Always
Created attachment 338166 [details] modified mesa-progs-8.0.1.ebuild
Already in the overlay. Waiting for a new release of mesa-demos to do this. Should happen soon. I like that your ebuild is able to build them without running configure. The ebuild in the overlay also builds es1/2gears which requires running configure. Maybe they're not worth building?
The release is out now, worked well for me to just copy the old ebuild and rename it. I've added it to my layman repo (AzP) as well, but I guess it's quicker for you to do the same than to get it from my repo =)
Fixed in 8.1.0